This article was first published in 2013. The content and structure in the current version do not yet cover all the key aspects we intend to cover. We plan to revise and extend the material in the future.

The levels of violence in prehistoric times (archeological evidence) and in non-state societies (ethnographic evidence) was much higher than in modern state societies and in the world today. This is what the data tells us, and I have visualized this evidence in a series of barcharts.

For the study of lethal violence in non-state societies we have generally two different sources of information; for the more recent past (since the late 19th century) abundant ethnographic evidence is available. For the more distant past, we have information on the prevalence of violence from archeologists who have studied violence in past societies by studying archeological sites and skeletal remains. They present data on the share of people that died in violent conflict with other humans in scientific studies. Data from both archaeological and ethnographic studies is presented in the dataset on this website, but it is not all the information we have on violence in different societies. Non-quantitative information on violence is abundant; for example through forms of art.

Empirical View

I have collected data on violent deaths; the long list of sources can be found below. These data show that in prehistoric times (archeological evidence) and in non-state societies (ethnographic evidence) the levels of violence was much higher than in modern state societies and in the world today.

Share of Violent Deaths in Prehistoric Archeological, State and Non-State Societies

Data Quality & Definition

Unit of Measurement: Rates vs Shares

There are two ways to state the frequency of homicides in populations: rates and shares. For modern societies, homicide rates are usually given as homicides per 100,000 people per year; for more violent societies described by archeologists and ethnologists, homicide rates are sometimes presented in homicides per 1000 people per year. Homicide shares are simply the percentage of a sample of deaths that were due to homicide.

Distinguishing between War and Murders

The word 'war' evokes the image of large scale battles; indeed the modern literature considers an armed conflict to be a war 'if at least 1,000 battle or battle-related deaths are inflicted in the indicated year'.11 It is important to make clear that the aforementioned association of the word and the modern definition are not applicable to lethal conflicts among small societies. What is common to both the definition of warfare among small and large societies is that the conflict is fought between different groups of people. One drawback of my database is that it was not always possible to distinguish between violence killings inflicted by members of the same groups and killings inflicted by members of a different groups. In small societies without a state authority, the violence between different groups is typically higher than among members of the same group. The reason why this distinction is hard to make is obvious for archeological evidence. For data based on ethnographic studies, I commented on the distinction between inter- and intra-group killings. Nevertheless, this dataset would be improved if the distinction would always be made.

To make comparisons between levels of violence, I calculated the homicide shares and rates for modern state-societies by also including killings in both intra-group wars and inter-group homicides.

Data Sources

This is the collection of all my sources for data on ethnographic and archaeological evidence on violent deaths.

This data is presented in the entry on homicides.

My sources and procedure to collect this data

The starting point for my research was the sample presented by Pinker (2011).12 Pinker does not present the numerical data itself but instead includes two bar charts (Figures 2-2 and 2-3) from which the exact data cannot be discerned. Therefore I looked up all the sources for the data he presents.

The topic of Pinker's book is the decline of violence in humanity's history. That would give him an incentive to cherry-pick data that suits his narrative. For this reason I had contact with several of his critics and asked them for their evidence. After this assessment of Pinker's data, I did not find any reason to assume that he cherry-picked. He included all the data that his sources included.

Through my contact with critics of Pinker's book I was referred to a critique of Pinker's data by Douglas Fry.13 Fry criticizes some of Pinker's data. I checked the original sources for the criticized information, referred to the criticisms and the original sources in my comments and corrected the data when the criticism was justified.

An additional source that I added to my dataset and which was not yet available to Pinker is a study published by Robert Walker and Drew Bailey (published in 2013).14

The main sources are the following:

I checked the following sources and collected the data these sources presented. For every information I also included the original source:

Bowles (2009) - Did Warfare Among Ancestral Hunter-Gatherers Affect the Evolution of Human Social Behaviors?. In Science, 324, 5932, 1293--1298.

Sources that my source quoted: For a first time period (1940-62) Knauft (1985) - Good company and violence: Sorcery and social action in a lowland New Guinea society. Berkeley:University of California Press. cites 778 violent deaths per 100,000 people per year. For a second time period (1959-68): Steadman (1971) - Neighbors and killers: Residence and dominance among the Hewa of New Guinea. Ph.D. diss., Australian National University, Canberra, Australia. cites 683 violent deaths per 100,000 people per year. I calculated the mean which is 731.

Comment: Gat (2006) writes 'among the Goilala, whose total population was barely over 150, there were 29 (predominantly men) killed during a period of 35 years'. I calculated the rate of violent deaths given assuming that the population was 150 (the lower bound of his estimate).

Comment and source that my source quoted: Knauft B (1985) Good Company and Violence. Berkeley. University of California Press. Knauft et al (1987) cite a violent death rate of 419 per 100,000 people per year.

Source that my source quoted: Ploeg, A. 1983. "The Establishment of the Pax Neerlandica in the Bokondini Area." In The Pacification of Melanesia, ed. M. Rodman and M Cooper, pp. 161-78. Lanham, Md.: University Press of America.

Comment: Gat (2006) quotes Jean Briggs with the following: ‘Readers of Canadian Inuit ethnography, my own Never in Anger (1970) in particular, have sometimes concluded that Inuit are always and everywhere paciﬁc. Nothing could be farther from the truth.’

Society: !Kung Bushmen of the Kalahari - Violent deaths per 100,000 people per year: (before the establishment of a state authority): 42 // (after the establishment of a state authority): 29

Comment: Quotation of Gat (2006): 'The rate for the !Kung Bushmen of the Kalahari, the famous ‘harmless people’, was 0.29 per 1,000 per year, and had been 0.42 before the coming of ﬁrm state authority'.

Own calculation: I am following Pinker calculating this data: White (2011)15 estimates a total number of deaths of all violent deaths in the 20th-century of 180 million deaths. Pinker assumes an average annual world population for the 20th century of 3 billion. (see his footnote 65 in chapter 2).

180.000.000 / 100 = 1.800.000 violent deaths per year. Divided by an annual population of 3.000.000.000 and multiplied by 100,000 is 60.

Own calculation: I am following Pinker calculating this data: From the US Census I know that the average population of the US over the 20th century was: 163,275,000 (The source for this data is U.S. Census.

The number of 'Total Deaths of U.S. Military Personnel Serving and Casualties' for the 20th century: 619,538 This is taken from Leland & Oboroceanu (2010)16.

According to this source these are the number of 'Total Deaths of U.S. Military Personnel Serving and Casualties':

Spanish-American War (1898-1901): 2,446

World War I (1917-1918): 116,516

World War II (1941-1946): 405,399

Korean War (1950-1953): 36,574

Vietnam Conflict (1964-1973): 58,220

Persian Gulf War (1990-1991): 383

The sum of total deaths is: 619.538.

That means in an average year of the 20th 6195.38 US citizens died in war. Therefore the number of war deaths per 100,000 of the US in the 20th century is 3.79 (including the deaths of US-Americans in the Spanish-American War in the 2 last years of the 19th century.

Own calculation: I am following Pinker calculating this data: The Human Security Report Project. (accessed April 2013). Miniatlas of human security. (World Bank) has data on the global number of war deaths and is available online.

The last year that this source has data for is 2007. These are the numbers by category:

Number of State-Based Battle Deaths: 16.773

Number of Non-State Battle Deaths: 1.865

Number of One Sided Violence Deaths: 3.501

The total sum of the above is: 22.139. The population of the earth in 2007 war 6.658.000.000 (World Bank). This means taking the whole planet together 0.33 of 100,000 people died in battles and one-sided violence.

Violence Death Shares

Ethnographic Data

The following statistics refer to the share of violent deaths out of all deaths in a given society.

Source that Gat (2006) quoted: J.A.Yost,‘Twenty years of contact: The mechanism of change in Wao (Auca) culture’, in N. A. Whitten (ed.), Cultural Transformation and Ethnicity in Modern Ecuador. Urbana, IL: University of Illinois, 1981, pp. 677–704; C. A. Robarchek and C. J. Robarchek, ‘Cultures of war and peace: A comparative study of Waorani and Semai’, in J. Silverberg and J. P. Gray (eds), Aggression and Peacefulness in Humans and Other Primates. New York: Oxford University Press, pp. 189–213.

Comment: Quote from Gat (2006): The tribe 'resembles the Yanomamo in their subsistence patterns and in the causes and style of ﬁghting'. The data is collected over five generations '60 % of adult deaths over ﬁve generations were caused by feuding and warfare'.

Source that Walker and Bailey (2013) quoted: Larrick et al., 1979

Comment: 60% of victims were male. Total numbers: 272 killings in 484 deaths

Source that my source quoted: J.B. Ross -- A balance of deaths: Revenge feuding among the Achuarä Jívaro of the northwest Peruvian AmazonColumbia University, New York (1988)

Comment: 69% of victims were male. Total numbers: 106 killings in 250 deaths

Society: Arawete Share of Violent Deaths: 35%

My source for the data: Walker and Bailey (2013)

Source that my source quoted: E. Viveiros de Castro -- From the enemy's point of view. Humanity and divinity in an Amazonian Society -- University of Chicago Press, Chicago (1992)

Society: Kayapo Share of Violent Deaths: 35%

My source for the data: Walker and Bailey (2013)

Source that my source quoted: Werner, D. W. (1980). The making of a Mekranoti chief: The psychological and social determinants of leadership in a native South American Society. PhD dissertation. City University of New York, New York.

Comment: 75% of victims were male, Total numbers: 83 killings in 237 deaths

Comment: Warner estimated 200 violent deaths of a population of 700 men. total population was 3000 but he mentions no violent mortality of women and children. Bowles (2009) calculated the number for adult mortality due to violence/warfare. Keeley (1996) also quotes a share of violent deaths of 28% for the male Murngin population (his source is Harris 1975. Culture, People, Nature. 2d ed. New York: Crowed.)

Society: (Hunter-Gatherer) Casiguran Agta (Philippines) Share of Violent Deaths:12% were attributed to homicide (In the less violent time period (1962-1977); adult male population). Between 1977 and 1984 the homicide rate is 326 homicides per 100,000 people per year. In this time period, that was described as unusually violent (and which is therefore not quoted in my statistic) 21% of all adult male deaths were due to homicide (see comment).

Comment: The source of Pinker on the percentage of deaths in warfare is Bowles (2009) and he made a mistake that Fry (2013) corrects: Bowles (2009) based his calculation on ten killings when in fact 9 killings are reported. In the time between 1936 and 1950 not 10 but 9 Casiguran Agta were killed - 1 in 1950, 5 in 1947; 1 in1938 raid and 2 “shortly after World War II”. Bowles therefore miscalculated his data and Pinker carries this wrong number over.

As Headlands study of the Agta focusses on a later time (1962-84) I take the data from this better researched time. As Headland states that the latter half of his research stay (post-1977) was a time of 'unusual high violence' I quote the death rate due to violence from the earlier time (1962-77). In this more 'peaceful' time the share of violent deaths was 12% (and this also is not counting the number of killings of non-Agta by Agta - which is also high (see below)).

Homicides, as opposed to deaths in warfare are very common in the Agta Population as Headland points out: 'In the sample of adult male deaths before 1977, 12% were attributed to homicide; in 1977-1984, 21% of all adult male deaths were from homicide. The overall homicide rate for the Casiguran Agta, based on the data for 1977-1984, is 326 homicides per 100,000 people per year. The 14 homicides on which this calculation is based include only homicides of members of the de jure population.' (page 68).

He also notes that 'of the 33 Agta deaths by homicide since my arrival in 1962 up to June 1984, only eight were killed by non-Agta. Of the 14 Agta homicides in the de jure population in 1977-1984, only five were killed by non-Agta. Of the 53 homicides, only 30% of the victims were killed by non-Agta (16153)

And he says: 'It should be noted here that Agta kill outsiders, too. I know of 24 cases of Agta killing non-Agta since 1930 and 15 cases since I began fieldwork in the area in 1962.' (page 69)

Society: Anggor Share of Violent Deaths: 11.9%

My source for the data: Keeley (1996)

Source that my source quoted: Huber, P. 1973. "Defending the Cosmos: Violence and Social Order Among the Anggor of New Guinea." In War, Its Causes and Correlates, ed. M. Nettieship, R. Givens, and A. Nettieship, pp. 619-61. The Hague: Mouton.

Society: Gebusi Share of Violent Deaths: 8.3%

My source for the data: Keeley (1996)

Source that my source quoted: Knauft B 1985 Good Company and Violence. Berkeley. University of California Press

Comment: Male Deaths: 8.3% - Female Deaths: 8.2%

Society: (Hunter-Gatherer) Hiwi Share of Violent Deaths: 7,2 % (Hiwi killed by Hiwi in Precontact times); in total 28% of Hiwi died a violent death in Precontact times

Comment: The paper distinguishes clearly between deaths inflicted by Venezuelans on Hiwis and death inflicted by Hiwis on Hiwis. Table 4 (page 450) shows the statistics on both groups and makes an additional distinction between precontact and postcontact times. In the precontact times 153 deaths are tabulated. There were 11 killings of Hiwi by Hiwi in the precontact times. Out of the 160 killings in the postcontact times 6 were killings of Hiwi by Hiwi. The Source that my source quoted states: "The Hiwi mortality proﬁle is characterized by notably high rates of violence and accidental trauma" (page 449)

The numbers I quoted and the share of violent deaths is not counting infanticides that were very common among the Hiwi (and are reported by Hill, Hurtado (2007)).

Gat (2006) refers to Pilling saying: 'Pilling’s estimate of at least 10 per cent killed among the Tiwi men in one decade.'

Gat (2006) refers to Kimber saying: 'Kimber’s estimate, for a generation, of 5 per cent mortality in ﬁghting in arid areas and about 6.5 per cent in well-watered ones refers to violent mortality in relation to the entire population’s overall mortality rates.' Pinker quotes the 10%, which according to Gat (2006) only refers to the male population. I decided to quote the average of the two shares specified for the entire population. That is 5.75%.

My own calculation:* The Human Security Report Project - Miniatlas of human security (accessed April 2013) has data on the global number of war deaths. It is available online

The last year that we have data for is 2007. These are the numbers by category:

Number of State-Based Battle Deaths: 16773

Number of Non-State Battle Deaths: 1865

Number of One Sided Violence Deaths: 3501

The total sum of the above is: 22139 deaths

The world population in 2007 was 6.658.000.000 (World Bank) - The death rate of the world is approximately 8 per 1000 per year according to the CIA Factbook. This means in 2007 around 53264000 people died in 2007. Therefore the ratio of people dying due to warfare in 2007 is 22139/53264000. This means 0.04% of the global deaths were due to warfare in 2007.

Archeological Data

Comment and Source that my source quoted: Keeley (1996) writes: 'Contrary to Brian Ferguson's claim that such slaughters were a consequence of contact with modem European or other civilizations, archaeology yields evidence of prehistoric massacres more severe than any recounted in ethnography.(Footnote 23- 23. (Middle Missouri) Zimmerman 1980; Wilky 1990; Bamforth 1994; (Southwest) Haas 1990: 187, and personal communication.) For example, at Crow Creek in South Dakota, archaeologists found a mass grave containing the remains of more than 500 men, women, and children who had been slaughtered, scalped, and mutilaced during an attack on their village a century and a hdf before Columbus's arrival (ca. A.D. 1325). The attack seems to have occurred just when the village's fortifications were being rebuilt. AU the houses were burned, and most of the inhabitants were murdered. This death toll represented more than 60 percent of the village's population, estimated from the number of houses to have been about 800. The survivors appear to have been primarily young women, as their skeletons are underrepresented among the bones; if so, they were probably taken away as captives. Certainly, the site was deserted for some time after the attack because the bodies evidently remained exposed to scavenging animals for a few weeks before burial. In other words, this whole village was annihilared in a single attack and never reoccupied.'

Comment: Here Pinker appears to have made a mistake by converting the dates from years before present to BCE/CE. Bowles gives the time period as '3140-2854 years before present' which Pinker erroneously converted to 2140-850 BCE.

Comment: Here Pinker appears to have made a mistake by converting the dates from years before present to BCE/CE. Bowles gives the time period as '2240-238 years before present' which Pinker erroneously converted to 240 - 1770 CE.

License: All of Our World in Data is completely open access and all work is licensed under the Creative Commons BY license. You have the permission to use, distribute, and reproduce in any medium, provided the source and authors are credited.